Rodrigues Lopes et al. have reported that the MSC cytokine pattern in AML patients includes elevated expression levels of CXCL12, VEGFA, PGE2, IL-1β, indoleamine 2,3-dioxygenase (IDO), IL-32, and IL-6, and reduced expression of IL-10. Here, IDO1 is linked to acute myeloid leukemia.